PULMONARY VESSELS. 331 



Fig. 248. SEMI-DIAGRAMMATIC VIEW OF THE ORGANS OP CIRCULATION IN THE Forrus 

 FROM BEFORE, (modified from Luschka and from Nature), f 



a, front of the thyroid cartilage ; 5, right side of the thyroid body ; c, trachea ; d t 

 surface of the right lung turned outwards from the heart ; e, diaphragm below the apex 

 of the heart ; /, right lobe of the liver, dissected to show ramifications of the portal and 

 hepatic veins ; /', the middle part and left lobe of the liver in the same manner, showing 

 branches of the umbilical veins and ductus venosus ; g, right, c/, left kidney ; g", supra- 

 renal bodies ; h, right, h', left ureter ; r, portion of the small intestine turned towards 

 the side, to show the veins from it going to the portal vein ; k, urinary bladder ; Z, is 

 placed below the umbilicus, which is turned towards the left of the fetus, and points 

 by a line to the urachus ; m, rectum, divided and tied at its upper part. 



A, A, right auricle of the heart opened to show the foramen ovale : a probe, intro- 

 duced through the large divided right hepatic vein and vena cava inferior, is seen passing 

 through the fossa ovalis into the left auricle : at the lower part of the fossa ovalis is seen 

 the Eustachian valve, to the right and inferiorly the auriculo-ventricular orifice ; B, the 

 left auricular appendix ; (7, the surface of the right ventricle ; D, placed on the inner 

 surface of the left lung, points to the left ventricle. 



1, ascending part of the arch of the aorta; I 7 , back part beyond the ductus arteriosus ; 

 1", abdominal aorta ; 2, stem of the pulmonary artery; 2', the place of division into 

 right and left pulmonary arteries and root of the ductus arteriosus : the left pneumo- 

 gastric nerve is seen descending over the arch of the aorta ; 3, superior vena cava ; 3', 

 right, 3", left innominate vein ; 4, stem of the inferior vena cava, between the junction 

 of the hepatic vein and the right auricle ; 4', continuation of the vena cava inferior below ; 

 5, umbilical vein within the body of the foetus ; 5 x , without the body, in the umbilical 

 cord ; 5', 5', ductus venosus ; between 5 and 5', the direct branches of the umbilical vein 

 to the liver ; 5", 5'', hepatic veins, through one of which a probe is passed into the fossa 

 ovalis and through the foramen ovale ; 6, vena portae ; 6', its left branch joining the 

 umbilical vein ; 6", its right branch ; 7, placed on the right iliac vein, points to the right 

 common iliac artery ; 7', left common iliac artery ; 8, right, 8', left umbilical arteries 

 coming from the internal iliac arteries ; 8 x , umbilical arteries without the body, in the 

 umbilical cord; 9, 9', external iliac arteries; 10, placed below the right renal vessels ; 

 11, inferior mesenteric artery, above the root of which are seen the two spermatic arteries. 



ment of an increased flow of blood through the lungs, which then perform their office 

 as respiratory organs. The foramen ovale, the ductus arteriosus, the ductus venosus, 

 and the umbilical vessels, all parts peculiar to the foetus, are gradually closed, and the 

 right and left cavities of the heart thenceforth cease to communicate directly with 

 each other. According to Bernt, the ductus arteriosus begins to contract imme- 

 diately after several inspirations have taken place : in three or four days he some- 

 times found it closed; on the eighth day it was obliterated in one half the cases 

 examined, and on the tenth day in all. The foramen ovale appears to continue open 

 a little longer, and it sometimes remains more or less so throughout life, as already 

 stated. The umbilical arteries, the umbilical vein, and the ductus venosus, shrink and 

 begin to be obliterated from the second to the fourth day after birth, and are gene- 

 rally completely closed by the fourth or fifth day. 



PULMONARY VESSELS. 



PULMONARY ARTERY AND VEINS. 



The pulmonary artery is a short wide vessel, which carries the dark blood 

 from the right side of the heart to the lungs. Tt arises from the infundi- 

 bulum or conus arteriosus of the right ventricle, and passes for the space of 

 nearly two inches upwards, and at the same time backwards and to the left 

 side, to reach the concavity of the aortic arch, where it divides into its 

 right and left branches. The mode of attachment of the pulmonary artery 

 to the base of the ventricle has already been fully noticed. At each side 

 of its commencement is the corresponding coronary artery springing from 

 the aorta, and close to its sides are the two auricular appendages. It 

 is at first in front of the aorta, and conceals the origin of that vessel ; 

 but higher up, where it lies in front of the left auricle, it crosses to the 

 left side of the ascending aorta, and is finally placed beneath the transverse 



z 2 



